We want to drive a 3D-stereo 720p DLP projector with Linux and the "Stereo 3" option in the driver. The PJ expects frame-sequential stereo like old-school quad stereo on a CRT - we tested it yesterday over VGA on a Quadro 3700 and it worked great.

Due to the location of the computer, we'd like to get this going over an HDMI port that will be installed in the wall so that it can carry the audio signal as well. Are there any nVidia cards that can do frame-sequential stereo over HDMI and support HDMI audio as well? Looking at their website is confusing because a lot of the products (e.g. GTX295) say they support stereoscopic 3D, HDMI, and HDMI audio (via SPDIF input in case of the GTX295), but there's no way to know if this support is only for their proprietary 3D Vision products on Windows, or if it also translates to Linux and a generic frame-sequential stereo display.

I'm not at all familiar with stereo, but I've been informed that: Any Quadro with a 3-pin stereo header will support stereo mode 3. As far as audio goes, any board with a GeForce 200 series GPU or later should support audio-over-HDMI.

Thanks for the quick reply. I don't know of any GTX series boards that have the 3-pin stereo sync port (the mini-DIN ports are S-video, right?). So I think that means we need a Quadro board that has GPU support for HDMI audio via the Intel HD-audio spec?

Yes, you'll certainly need a Quadro board. One with an HD-audio controller seems like the best bet. I'd take a look at Fermi Quadro boards. Sorry, I'm not that familiar with the exact cards in our Fermi Quadro lineup.